Industrial frequency electric induction furnace with submerged horizontal channel for the melting of any metal



July 23, 1963 E. E. CALAMARI 3,098,887

INDUSTRIAL F UENCY ELECTRIC INDUCTION FURNACE WITH su RGED HORIZONTAL CHANNEL FOR THE MELTING OF ANY METAL Filed Nov. 18, 1958 2 Sheets-Sheet 1 July 23, 1963 E. E. c A ARI 3,

INDUSTRIAL FREQUENCY ELEC I NDUCTION FURNACE WITH SUBMERGED H L FOR T E MEL L ZONTAL CHANNE v H G OF ANY META Filed Nov. 18, 1958 v 2 Sheets-Sheet 2 United States Patent 3,098,887 INDUSTRIAL FREQUENCY ELECTRIC INDUC- TION FURNACE WITH SUBMERGED HORIZON- TAL CHANNEL FOR THE MELTING OF ANY METAL Elio Ezio Calamari, Via dei Gelsomini 2, Milan, Italy Filed Nov. 18, 1958, Ser. No. 774,620 Claims priority, application Italy Nov. 28, 195

2 Claims. (Cl. 13-29) It is known that the first industrial frequency or low frequency electric induction furnace with a channel that was built, was an uncovered-channel induction furnace (Kjelling furnace), in which the metal to be melted constituted a short circuited secondary ring (channel) of an electric transformer.

At a later stage there was built a furnace based on the same principle, but with a vertical channel placed under the bottom of the melting basin (Ajax furnace); that furnace was employed for the melting of brass, bronze and copper.

Further on, in order to extend the use of such furnace to the melting of other metals and alloys such as aluminium and its alloys; iron and its alloys; precious metals, etc., the Ajax furnace underwent many modifications and there were built furnaces with a horizontal channel; an inclined channel; an uncovered channel (improved Kjelling); an oscillating channel (Calamari) with one or more inductor elements with single or double basin.

The present invention relates to an induction furnace of the kind of those mentioned above (low frequency with channel) wherein the secondary channel or channels are submerged in the mass of molten metal and form the bottom of the melting basin.

The inductor, constituted by the magnetic core, the primary coil and the secondary channel, is placed on the bottom of the melting crucible.

An inductor so conceived can be mounted separate from the furnace and can be assembled therewith and disassembled therefrom with extreme easiness; moreover it can be applied to any other type of induction, resistor or fuel furnace.

A furnace mounted with this inductor may be employed for the melting of any metal or alloy and affords the following main advantages over the already known induction furnaces:

(a) The power/capacity ratio can be minimized;

(b) Very high power factor;

(0) Feeding by constant voltage and, therefore, at constant power;

(d) Melting crucible completely free;

(e) Starting from cold metal (self-starting);

(f) Easy replacement of the inductor even while furnace is hot;

(g) Easy change of the alloy or metal being melted;

(h) Easiness of elaborating (Working out) and scorifying (slagging) the alloys;

(1) The submerged channels can be easily inspected during running and do not require any drain plugs for any metal or alloy;

(1') With the same inductor it is possible to build furnaces with one or more basins;

(k) The secondary channels being submerged by the 3,098,887 Patented July 23, 1963 molten mass and forming part in turn of that mass, are not overheated and, therefore, the temperature in the molten mass is more uniform;

(l) The furnace has no projecting parts and, therefore in addition to occupying a smaller space with respect to common induction furnaces, it has lower heat loss and, therefore, higher thermal efficiency;

(m) The quantity of metal to maintain the furnace primed, is small with respect to the capacity of the furnace.

The invention will be more fully described hereinafter, by Way of example, with respect also to the accompanying drawing wherein:

FIG. 1 represents in elevation the instant furnace by a sect-ion taken along a vertical axis;

FIG. 2 represents the same furnace by a horizontal section taken along a plane passing through the line XY indicated in FIGURE 1; and

FIG. 3 represents the same furnace in perspective view partly in section taken: along the line Z-Z of FIG. 2.

With reference to FIGURE 1 wherein there is shown a vertical section of a furnace of conventional construction, it is seen that A indicates the basin or melting chamber and B the inductor.

The inductor B comprises a magnetic core 1; a primary coil 2.; a circular or longitudinal tubular coil or watercooling chamber 3 wound up on the yoke of the core 1; a refractory lining 4 projecting into the basin A and defining secondary channels.

In FIGURE 1 there is also visible the application of the inductor to the melting basin through external fastening screws 6 and an annular gasket of fused cement or asbestos 7 in the interior.

In FIGURE 2 there is shown a horizontal section at the height of the plane XY of the inductor, and therein is visible parts of a closed channel 8 and parts of an open channel 9.

In FIGURE 3 there are particularly well visible the cooling coils 3 around the yoke. In that figure, E indicates the imaginary secondary rings formed by the metal G in the vertical uncovered channels.

It will be noted that the joining plane of the top section and the lower section of the melting chamber is substantially at the level of the coil shaped cooling chambers 3. This provides convenient access for installing, replacing or repairing said cooling chambers. Said coil-shaped cooling chambers may be employed either as independent primary coils or concurrently with the main coil 2 to provide increased inductive heating action.

Obviously there may be foreseen other cases of application of the above described inductor with melting chambers having different shapes.

I claim:

1. An industrial frequency electric induction furnace for the melting of metal or metallic alloy comprising a melting chamber, an inductor housing located transversely of said chamber, said inductor housing having a magnetic core therein and a yoke above said core and at right angles therewith, a primary coil spaced from and mounted about said magnetic core, at least one coilshaped cooling chamber spaced from and mounted about said yoke and acting as a primary inductor coil, and a refractory lining enclosing said magnetic core, said yoke and said cooling chamber and extending across said melting chamber to divide the bottom portion thereof into two vertical compartments, said refractory lining being formed with at least one through passage located below the cooling chamber and establishing a permanent communication between said two vertical compartments, said melting chamber comprising a top section and a lower section joining in a horizontal plane substantially at the level of said cooling chamber, whereby to at times provide access to said cooling chamber.

2. The structure of claim 1, and an annular gasket of molten cement and powdered asbestos recessed in the rim of one of the sections.

References Cited in the file of this patent UNITED STATES PATENTS Summey June 15, 1926 Foley Aug. 30, 1927 Brace Jan. 10, 1928 Schunk Aug. 4, 1942 Tama et al. Nov. 20, 1945 Range Jan. 23, 1951 

1. AN INDUSTRIAL FREQUENCY ELECTRIC INDUCTION FURNACE FOR THE MELTING OF METAL OR METALLIC ALLOY COMPRISING A MELTING CHAMBER, AN INDUCTOR HOUSING LOCATED TRANSVERSELY OF SAID CHAMBER, SAID INDUCTOR HOUSING HAVING A MAGNETIC CORE THEREIN AND A YOKE ABOVE SAID CORE AND AT RIGHT ANGLES THEREWITH, A PRIMARY COIL SPACED FROM AND MOUNTED ABOUT SAID MAGNETIC CORE, AT LEAST ONE COILSHAPED COOLING CHAMBER SPACED FROM AND MOUNTED ABOUT SAID YOKE AND ACTING AS A PRIMARY INDUCTOR COIL, AND A REFRACTORY LINING ENCLOSING SAID MAGNETIC CORE, SAID YOKE AND SAID COOLING CHAMBER AND EXTENDING ACROSS SAID MELTING CHAMBER TO DIVIDE THE BOTTOM PORTION THEREOF INTO TWO VERTICAL COMPARTMENTS, SAID REFRACTORY LINING BEING FORMED WITH AT LEAST ONE THROUGH PASSAGE LOCATED BELOW THE COOLING CHAMBER AND ESTABLISHING A PERMANENT COMMUNICATION BETWEEN SAID TWO VERTICAL COMPARTMENTS, SAID MELTING CHAMBER COMPRISING A TOP SECTION AND A LOWER SECTION JOINING IN A HORIZONTAL PLANE SUBSTANTIALLY AT THE LEVEL OF SAID COOLING CHAMBER, WHEREBY TO AT TIMES PROVIDE ACCESS TO SAID COOLING CHAMBER. 